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2021-05-13virtiofsd: Fix check of chown()'s return valueGreg Kurz1-2/+2
Otherwise you always get this warning when using --socket-group=users vhost socket failed to set group to users (100) While here, print out the error if chown() fails. Fixes: f6698f2b03b0 ("tools/virtiofsd: add support for --socket-group") Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <162040394890.714971.15502455176528384778.stgit@bahia.lan> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2021-05-06virtiofsd/fuse_virtio.c: Changed allocations of locals to GLibMahmoud Mandour1-6/+5
Replaced the allocation of local variables from malloc() to GLib allocation functions. In one instance, dropped the usage to an assert after a malloc() call and used g_malloc() instead. Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210420154643.58439-8-ma.mandourr@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-06virtiofsd/passthrough_ll.c: Changed local allocations to GLib functionsMahmoud Mandour1-11/+6
Changed the allocations of some local variables to GLib's allocation functions, such as g_try_malloc0(), and annotated those variables as g_autofree. Subsequently, I was able to remove the calls to free(). Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210420154643.58439-7-ma.mandourr@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-06virtiofsd: Changed allocations of fv_VuDev & its internals to GLib functionsMahmoud Mandour1-13/+6
Changed the allocations of fv_VuDev structs, VuDev structs, and fv_QueueInfo strcuts from using calloc()/realloc() & free() to using the equivalent functions from GLib. In instances, removed the pair of allocation and assertion for non-NULL checking with a GLib function that aborts on error. Removed NULL-checking for fv_VuDev struct allocation and used a GLib function that crashes on error; namely, g_new0(). This is because allocating one struct should not be a problem on an healthy system. Also following the pattern of aborting-on-null behaviour that is taken with allocating VuDev structs and fv_QueueInfo structs. Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210420154643.58439-6-ma.mandourr@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-06virtiofsd: Changed allocation of lo_map_elems to GLib's functionsMahmoud Mandour1-2/+2
Replaced (re)allocation of lo_map_elem structs from realloc() to GLib's g_try_realloc_n() and replaced the respective free() call with a g_free(). Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210420154643.58439-5-ma.mandourr@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-06virtiofsd: Changed allocations of fuse_session to GLib's functionsMahmoud Mandour1-3/+3
Replaced the allocation and deallocation of fuse_session structs from calloc() and free() calls to g_try_new0() and g_free(). Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210420154643.58439-4-ma.mandourr@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-06virtiofsd: Changed allocations of iovec to GLib's functionsMahmoud Mandour2-24/+14
Replaced the calls to malloc()/calloc() and their respective calls to free() of iovec structs with GLib's allocation and deallocation functions and used g_autofree when appropriate. Replaced the allocation of in_sg_cpy to g_new() instead of a call to calloc() and a null-checking assertion. Not g_new0() because the buffer is immediately overwritten using memcpy. Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Message-Id: <20210427181333.148176-1-ma.mandourr@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-06virtiofsd: Changed allocations of fuse_req to GLib functionsMahmoud Mandour1-3/+3
Replaced the allocation and deallocation of fuse_req structs using calloc()/free() call pairs to a GLib's g_try_new0() and g_free(). Signed-off-by: Mahmoud Mandour <ma.mandourr@gmail.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210420154643.58439-2-ma.mandourr@gmail.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-05-06virtiofsd: Don't assume header layoutDr. David Alan Gilbert1-21/+73
virtiofsd incorrectly assumed a fixed set of header layout in the virt queue; assuming that the fuse and write headers were conveniently separated from the data; the spec doesn't allow us to take that convenience, so fix it up to deal with it the hard way. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210428110100.27757-3-dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-05-06virtiofs: Fixup printf argsDr. David Alan Gilbert1-10/+11
Fixup some fuse_log printf args for 32bit compatibility. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210428110100.27757-2-dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-05-06virtiofsd: Add help for -o xattr-mappingCarlos Venegas1-0/+3
The option is not documented in help. Add small help about the option. Signed-off-by: Carlos Venegas <jose.carlos.venegas.munoz@intel.com> Message-Id: <20210414201207.3612432-3-jose.carlos.venegas.munoz@intel.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
2021-05-06virtiofsd: Allow use "-o xattrmap" without "-o xattr"Carlos Venegas1-0/+1
When -o xattrmap is used, it will not work unless xattr is enabled. This patch enables xattr when -o xattrmap is used. Signed-off-by: Carlos Venegas <jose.carlos.venegas.munoz@intel.com> Message-Id: <20210414201207.3612432-2-jose.carlos.venegas.munoz@intel.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Connor Kuehl <ckuehl@redhat.com>
2021-05-06virtiofsd: Fix side-effect in assert()Greg Kurz1-8/+13
It is bad practice to put an expression with a side-effect in assert() because the side-effect won't happen if the code is compiled with -DNDEBUG. Use an intermediate variable. Consolidate this in an macro to have proper line numbers when the assertion is hit. virtiofsd: ../../tools/virtiofsd/passthrough_ll.c:2797: lo_getxattr: Assertion `fchdir_res == 0' failed. Aborted 2796 /* fchdir should not fail here */ =>2797 FCHDIR_NOFAIL(lo->proc_self_fd); 2798 ret = getxattr(procname, name, value, size); 2799 FCHDIR_NOFAIL(lo->root.fd); Fixes: bdfd66788349 ("virtiofsd: Fix xattr operations") Cc: misono.tomohiro@jp.fujitsu.com Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210409100627.451573-1-groug@kaod.org> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
2021-04-06virtiofsd: Fix security.capability comparisonDr. David Alan Gilbert1-1/+2
My security fix for the security.capability remap has a silly early segfault in a simple case where there is an xattrmapping but it doesn't remap the security.capability. Fixes: e586edcb41054 ("virtiofs: drop remapped security.capability xattr as needed") Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210401145845.78445-1-dgilbert@redhat.com> Reviewed-by: Connor Kuehl <ckuehl@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-03-24tools/virtiofsd: include --socket-group in helpAlex Bennée1-0/+1
I confused myself wandering if this had been merged by looking at the help output. It seems fuse_opt doesn't automagically add to help output so lets do it now. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Connor Kuehl <ckuehl@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Updates: f6698f2b03 ("tools/virtiofsd: add support for --socket-group") Message-Id: <20210323165308.15244-5-alex.bennee@linaro.org>
2021-03-15virtiofsd: Convert some functions to return boolGreg Kurz1-3/+3
Both currently only return 0 or 1. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210312141003.819108-3-groug@kaod.org> Reviewed-by: Connor Kuehl <ckuehl@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-03-15virtiofsd: Don't allow empty paths in lookup_name()Greg Kurz1-2/+1
When passed an empty filename, lookup_name() returns the inode of the parent directory, unless the parent is the root in which case the st_dev doesn't match and lo_find() returns NULL. This is because lookup_name() passes AT_EMPTY_PATH down to fstatat() or statx(). This behavior doesn't quite make sense because users of lookup_name() then pass the name to unlinkat(), renameat() or renameat2(), all of which will always fail on empty names. Drop AT_EMPTY_PATH from the flags in lookup_name() so that it has the consistent behavior of "returning an existing child inode or NULL" for all directories. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210312141003.819108-2-groug@kaod.org> Reviewed-by: Connor Kuehl <ckuehl@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-03-15virtiofsd: Don't allow empty filenamesGreg Kurz1-0/+35
POSIX.1-2017 clearly stipulates that empty filenames aren't allowed ([1] and [2]). Since virtiofsd is supposed to mirror the host file system hierarchy and the host can be assumed to be linux, we don't really expect clients to pass requests with an empty path in it. If they do so anyway, this would eventually cause an error when trying to create/lookup the actual inode on the underlying POSIX filesystem. But this could still confuse some code that wouldn't be ready to cope with this. Filter out empty names coming from the client at the top level, so that the rest doesn't have to care about it. This is done everywhere we already call is_safe_path_component(), but in a separate helper since the usual error for empty path names is ENOENT instead of EINVAL. [1] https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_170 [2] https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_13 Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210312141003.819108-4-groug@kaod.org> Reviewed-by: Connor Kuehl <ckuehl@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-03-15virtiofsd: Add qemu version and copyright infoVivek Goyal1-0/+8
Option "-V" currently displays the fuse protocol version virtiofsd is using. For example, I see this. $ ./virtiofsd -V "using FUSE kernel interface version 7.33" People also want to know software version of virtiofsd so that they can figure out if a certain fix is part of currently running virtiofsd or not. Eric Ernst ran into this issue. David Gilbert thinks that it probably is best that we simply carry the qemu version and display that information given we are part of qemu tree. So this patch enhances version information and also adds qemu version and copyright info. Not sure if copyright information is supposed to be displayed along with version info. Given qemu-storage-daemon and other utilities are doing it, so I continued with same pattern. This is how now output looks like. $ ./virtiofsd -V virtiofsd version 5.2.50 (v5.2.0-2357-gcbcf09872a-dirty) Copyright (c) 2003-2020 Fabrice Bellard and the QEMU Project developers using FUSE kernel interface version 7.33 Reported-by: Eric Ernst <eric.g.ernst@gmail.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Message-Id: <20210303195339.GB3793@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Sergio Lopez <slp@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-03-15virtiofsd: Release vu_dispatch_lock when stopping queueGreg Kurz1-0/+6
QEMU can stop a virtqueue by sending a VHOST_USER_GET_VRING_BASE request to virtiofsd. As with all other vhost-user protocol messages, the thread that runs the main event loop in virtiofsd takes the vu_dispatch lock in write mode. This ensures that no other thread can access virtqueues or memory tables at the same time. In the case of VHOST_USER_GET_VRING_BASE, the main thread basically notifies the queue thread that it should terminate and waits for its termination: main() virtio_loop() vu_dispatch_wrlock() vu_dispatch() vu_process_message() vu_get_vring_base_exec() fv_queue_cleanup_thread() pthread_join() Unfortunately, the queue thread ends up calling virtio_send_msg() at some point, which itself needs to grab the lock: fv_queue_thread() g_list_foreach() fv_queue_worker() fuse_session_process_buf_int() do_release() lo_release() fuse_reply_err() send_reply() send_reply_iov() fuse_send_reply_iov_nofree() fuse_send_msg() virtio_send_msg() vu_dispatch_rdlock() <-- Deadlock ! Simply have the main thread to release the lock before going to sleep and take it back afterwards. A very similar patch was already sent by Vivek Goyal sometime back: https://listman.redhat.com/archives/virtio-fs/2021-January/msg00073.html The only difference here is that this done in fv_queue_set_started() because fv_queue_cleanup_thread() can also be called from virtio_loop() without the lock being held. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210312092212.782255-8-groug@kaod.org> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-03-04virtiofs: drop remapped security.capability xattr as neededDr. David Alan Gilbert1-1/+76
On Linux, the 'security.capability' xattr holds a set of capabilities that can change when an executable is run, giving a limited form of privilege escalation to those programs that the writer of the file deemed worthy. Any write causes the 'security.capability' xattr to be dropped, stopping anyone from gaining privilege by modifying a blessed file. Fuse relies on the daemon to do this dropping, and in turn the daemon relies on the host kernel to drop the xattr for it. However, with the addition of -o xattrmap, the xattr that the guest stores its capabilities in is now not the same as the one that the host kernel automatically clears. Where the mapping changes 'security.capability', explicitly clear the remapped name to preserve the same behaviour. This bug is assigned CVE-2021-20263. Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com>
2021-02-16virtiofsd: Do not use a thread pool by defaultVivek Goyal1-1/+1
Currently we created a thread pool (With 64 max threads per pool) for each virtqueue. We hoped that this will provide us with better scalability and performance. But in practice, we are getting better numbers in most of the cases when we don't create a thread pool at all and a single thread per virtqueue receives the request and processes it. Hence, I am proposing that we switch to no thread pool by default (equivalent of --thread-pool-size=0). This will provide out of box better performance to most of the users. In fact other users have confirmed that not using a thread pool gives them better numbers. So why not use this as default. It can be changed when somebody can fix the issues with thread pool performance. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Message-Id: <20210210182744.27324-2-vgoyal@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-16viriofsd: Add support for FUSE_HANDLE_KILLPRIV_V2Vivek Goyal4-8/+103
This patch adds basic support for FUSE_HANDLE_KILLPRIV_V2. virtiofsd can enable/disable this by specifying option "-o killpriv_v2/no_killpriv_v2". By default this is enabled as long as client supports it Enabling this option helps with performance in write path. Without this option, currently every write is first preceeded with a getxattr() operation to find out if security.capability is set. (Write is supposed to clear security.capability). With this option enabled, server is signing up for clearing security.capability on every WRITE and also clearing suid/sgid subject to certain rules. This gets rid of extra getxattr() call for every WRITE and improves performance. This is true when virtiofsd is run with option -o xattr. What does enabling FUSE_HANDLE_KILLPRIV_V2 mean for file server implementation. It needs to adhere to following rules. Thanks to Miklos for this summary. - clear "security.capability" on write, truncate and chown unconditionally - clear suid/sgid in case of following. Note, sgid is cleared only if group executable bit is set. o setattr has FATTR_SIZE and FATTR_KILL_SUIDGID set. o setattr has FATTR_UID or FATTR_GID o open has O_TRUNC and FUSE_OPEN_KILL_SUIDGID o create has O_TRUNC and FUSE_OPEN_KILL_SUIDGID flag set. o write has FUSE_WRITE_KILL_SUIDGID >From Linux VFS client perspective, here are the requirements. - caps are always cleared on chown/write/truncate - suid is always cleared on chown, while for truncate/write it is cleared only if caller does not have CAP_FSETID. - sgid is always cleared on chown, while for truncate/write it is cleared only if caller does not have CAP_FSETID as well as file has group execute permission. virtiofsd implementation has not changed much to adhere to above ruls. And reason being that current assumption is that we are running on Linux and on top of filesystems like ext4/xfs which already follow above rules. On write, truncate, chown, seucurity.capability is cleared. And virtiofsd drops CAP_FSETID if need be and that will lead to clearing of suid/sgid. But if virtiofsd is running on top a filesystem which breaks above assumptions, then it will have to take extra actions to emulate above. That's a TODO for later when need arises. Note: create normally is supposed to be called only when file does not exist. So generally there should not be any question of clearing setuid/setgid. But it is possible that after client checks that file is not present, some other client creates file on server and this race can trigger sending FUSE_CREATE. In that case, if O_TRUNC is set, we should clear suid/sgid if FUSE_OPEN_KILL_SUIDGID is also set. v3: - Resolved conflicts due to lo_inode_open() changes. - Moved capability code in lo_do_open() so that both lo_open() and lo_create() can benefit from common code. - Dropped changes to kernel headers as these are part of qemu already. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210208224024.43555-3-vgoyal@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-16virtiofsd: Save error code early at the failure callsiteVivek Goyal1-4/+5
Change error code handling slightly in lo_setattr(). Right now we seem to jump to out_err and assume that "errno" is valid and use that to send reply. But if caller has to do some other operations before jumping to out_err, then it does the dance of first saving errno to saverr and the restore errno before jumping to out_err. This makes it more confusing. I am about to make more changes where caller will have to do some work after error before jumping to out_err. I found it easier to change the convention a bit. That is caller saves error in "saverr" before jumping to out_err. And out_err uses "saverr" to send error back and does not rely on "errno" having actual error. v3: Resolved conflicts in lo_setattr() due to lo_inode_open() changes. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20210208224024.43555-2-vgoyal@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-16tools/virtiofsd: Replace the word 'whitelist'Philippe Mathieu-Daudé2-9/+9
Follow the inclusive terminology from the "Conscious Language in your Open Source Projects" guidelines [*] and replace the words "whitelist" appropriately. [*] https://github.com/conscious-lang/conscious-lang-docs/blob/main/faq.md Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20210205171817.2108907-3-philmd@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-16virtiofsd: vu_dispatch locking should never failGreg Kurz1-14/+35
pthread_rwlock_rdlock() and pthread_rwlock_wrlock() can fail if a deadlock condition is detected or the current thread already owns the lock. They can also fail, like pthread_rwlock_unlock(), if the mutex wasn't properly initialized. None of these are ever expected to happen with fv_VuDev::vu_dispatch_rwlock. Some users already check the return value and assert, some others don't. Introduce rdlock/wrlock/unlock wrappers that just do the former and use them everywhere for improved consistency and robustness. This is just cleanup. It doesn't fix any actual issue. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210203182434.93870-1-groug@kaod.org> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-16virtiofsd: Allow to build it without the toolsWainer dos Santos Moschetta1-2/+5
This changed the Meson build script to allow virtiofsd be built even though the tools build is disabled, thus honoring the --enable-virtiofsd option. Fixes: cece116c939d219070b250338439c2d16f94e3da (configure: add option for virtiofsd) Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com> Message-Id: <20210201211456.1133364-2-wainersm@redhat.com> Reviewed-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-04virtiofsd: Add restart_syscall to the seccomp whitelistGreg Kurz1-0/+1
This is how linux restarts some system calls after SIGSTOP/SIGCONT. This is needed to avoid virtiofsd termination when resuming execution under GDB for example. Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210201193305.136390-1-groug@kaod.org> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-04virtiofsd: Add _llseek to the seccomp whitelistGreg Kurz1-0/+1
This is how glibc implements lseek(2) on POWER. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1917692 Signed-off-by: Greg Kurz <groug@kaod.org> Message-Id: <20210121171540.1449777-1-groug@kaod.org> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-04virtiofsd: prevent opening of special files (CVE-2020-35517)Stefan Hajnoczi1-52/+92
A well-behaved FUSE client does not attempt to open special files with FUSE_OPEN because they are handled on the client side (e.g. device nodes are handled by client-side device drivers). The check to prevent virtiofsd from opening special files is missing in a few cases, most notably FUSE_OPEN. A malicious client can cause virtiofsd to open a device node, potentially allowing the guest to escape. This can be exploited by a modified guest device driver. It is not exploitable from guest userspace since the guest kernel will handle special files inside the guest instead of sending FUSE requests. This patch fixes this issue by introducing the lo_inode_open() function to check the file type before opening it. This is a short-term solution because it does not prevent a compromised virtiofsd process from opening device nodes on the host. Restructure lo_create() to try O_CREAT | O_EXCL first. Note that O_CREAT | O_EXCL does not follow symlinks, so O_NOFOLLOW masking is not necessary here. If the file exists and the user did not specify O_EXCL, open it via lo_do_open(). Reported-by: Alex Xu <alex@alxu.ca> Fixes: CVE-2020-35517 Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210204150208.367837-4-stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-04virtiofsd: optionally return inode pointer from lo_do_lookup()Stefan Hajnoczi1-8/+21
lo_do_lookup() finds an existing inode or allocates a new one. It increments nlookup so that the inode stays alive until the client releases it. Existing callers don't need the struct lo_inode so the function doesn't return it. Extend the function to optionally return the inode. The next commit will need it. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Message-Id: <20210204150208.367837-3-stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-02-04virtiofsd: extract lo_do_open() from lo_open()Stefan Hajnoczi1-27/+46
Both lo_open() and lo_create() have similar code to open a file. Extract a common lo_do_open() function from lo_open() that will be used by lo_create() in a later commit. Since lo_do_open() does not otherwise need fuse_req_t req, convert lo_add_fd_mapping() to use struct lo_data *lo instead. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20210204150208.367837-2-stefanha@redhat.com> Reviewed-by: Greg Kurz <groug@kaod.org> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2021-01-06cap_ng: convert to mesonPaolo Bonzini1-2/+2
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2021-01-06seccomp: convert to mesonPaolo Bonzini1-2/+2
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-18virtiofsd: Remove useless code about send_notify_iovAlex Chen1-98/+0
The 'ch' will be NULL in the following stack: send_notify_iov()->fuse_send_msg()->virtio_send_msg(), and this may lead to NULL pointer dereferenced in virtio_send_msg(). But send_notify_iov() was never called, so remove the useless code about send_notify_iov() to fix this problem. Signed-off-by: Alex Chen <alex.chen@huawei.com> Message-Id: <20201214121615.29967-1-alex.chen@huawei.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-18virtiofsd: update FUSE_FORGET comment on "lo_inode.nlookup"Laszlo Ersek1-1/+1
Miklos confirms it's *only* the FUSE_FORGET request that the client can use for decrementing "lo_inode.nlookup". Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Fixes: 1222f015558fc34cea02aa3a5a92de608c82cec8 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20201208073936.8629-1-lersek@redhat.com> Reviewed-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-18virtiofsd: Check file type in lo_flush()Vivek Goyal1-0/+6
Currently lo_flush() is written in such a way that it expects to receive a FLUSH requests on a regular file (and not directories). For example, we call lo_fi_fd() which searches lo->fd_map. If we open directories using opendir(), we keep don't keep track of these in lo->fd_map instead we keep them in lo->dir_map. So we expect lo_flush() to be called on regular files only. Even linux fuse client calls FLUSH only for regular files and not directories. So put a check for filetype and return EBADF if lo_flush() is called on a non-regular file. Reported-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Message-Id: <20201211142544.GB3285@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-18virtiofsd: Disable posix_lock hash table if remote locks are not enabledVivek Goyal1-17/+34
If remote posix locks are not enabled (lo->posix_lock == false), then disable code paths taken to initialize inode->posix_lock hash table and corresponding destruction and search etc. lo_getlk() and lo_setlk() have been modified to return ENOSYS if daemon does not support posix lock but client still sends a lock/unlock request. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Message-Id: <20201207183021.22752-3-vgoyal@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-18virtiofsd: Set up posix_lock hash table for root inodeVivek Goyal1-0/+7
We setup per inode hash table ->posix_lock to support remote posix locks. But we forgot to initialize this table for root inode. Laszlo managed to trigger an issue where he sent a FUSE_FLUSH request for root inode and lo_flush() found inode with inode->posix_lock NULL and accessing this table crashed virtiofsd. May be we can get rid of initializing this hash table for directory objects completely. But that optimization is for another day. Reported-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Message-Id: <20201207195539.GB3107@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-18virtiofsd: make the debug log timestamp on stderr more human-readableLaszlo Ersek1-4/+27
The current timestamp format doesn't help me visually notice small jumps in time ("small" as defined on human scale, such as a few seconds or a few ten seconds). Replace it with a local time format where such differences stand out. Before: > [13316826770337] [ID: 00000004] unique: 62, opcode: RELEASEDIR (29), nodeid: 1, insize: 64, pid: 1 > [13316826778175] [ID: 00000004] unique: 62, success, outsize: 16 > [13316826781156] [ID: 00000004] virtio_send_msg: elem 0: with 1 in desc of length 16 > [15138279317927] [ID: 00000001] virtio_loop: Got VU event > [15138279504884] [ID: 00000001] fv_queue_set_started: qidx=1 started=0 > [15138279519034] [ID: 00000003] fv_queue_thread: kill event on queue 1 - quitting > [15138280876463] [ID: 00000001] fv_remove_watch: TODO! fd=9 > [15138280897381] [ID: 00000001] virtio_loop: Waiting for VU event > [15138280946834] [ID: 00000001] virtio_loop: Got VU event > [15138281175421] [ID: 00000001] virtio_loop: Waiting for VU event > [15138281182387] [ID: 00000001] virtio_loop: Got VU event > [15138281189474] [ID: 00000001] virtio_loop: Waiting for VU event > [15138309321936] [ID: 00000001] virtio_loop: Unexpected poll revents 11 > [15138309434150] [ID: 00000001] virtio_loop: Exit (Notice how you don't (easily) notice the gap in time after "virtio_send_msg", and especially the amount of time passed is hard to estimate.) After: > [2020-12-08 06:43:22.58+0100] [ID: 00000004] unique: 51, opcode: RELEASEDIR (29), nodeid: 1, insize: 64, pid: 1 > [2020-12-08 06:43:22.58+0100] [ID: 00000004] unique: 51, success, outsize: 16 > [2020-12-08 06:43:22.58+0100] [ID: 00000004] virtio_send_msg: elem 0: with 1 in desc of length 16 > [2020-12-08 06:43:29.34+0100] [ID: 00000001] virtio_loop: Got VU event > [2020-12-08 06:43:29.34+0100] [ID: 00000001] fv_queue_set_started: qidx=1 started=0 > [2020-12-08 06:43:29.34+0100] [ID: 00000003] fv_queue_thread: kill event on queue 1 - quitting > [2020-12-08 06:43:29.34+0100] [ID: 00000001] fv_remove_watch: TODO! fd=9 > [2020-12-08 06:43:29.34+0100] [ID: 00000001] virtio_loop: Waiting for VU event > [2020-12-08 06:43:29.34+0100] [ID: 00000001] virtio_loop: Got VU event > [2020-12-08 06:43:29.34+0100] [ID: 00000001] virtio_loop: Waiting for VU event > [2020-12-08 06:43:29.34+0100] [ID: 00000001] virtio_loop: Got VU event > [2020-12-08 06:43:29.34+0100] [ID: 00000001] virtio_loop: Waiting for VU event > [2020-12-08 06:43:29.37+0100] [ID: 00000001] virtio_loop: Unexpected poll revents 11 > [2020-12-08 06:43:29.37+0100] [ID: 00000001] virtio_loop: Exit Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Message-Id: <20201208055043.31548-1-lersek@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-18virtiofsd: Use --thread-pool-size=0 to mean no thread poolVivek Goyal1-9/+27
Right now we create a thread pool and main thread hands over the request to thread in thread pool to process. Number of threads in thread pool can be managed by option --thread-pool-size. In tests we have noted that many of the workloads are getting better performance if we don't use a thread pool at all and process all the requests in the context of a thread receiving the request. Hence give user an option to be able to run virtiofsd without using a thread pool. To implement this, I have used existing option --thread-pool-size. This option defines how many maximum threads can be in the thread pool. Thread pool size zero freezes thead pool. I can't see why will one start virtiofsd with a frozen thread pool (hence frozen file system). So I am redefining --thread-pool-size=0 to mean, don't use a thread pool. Instead process the request in the context of thread receiving request from the queue. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Message-Id: <20201109143548.GA1479853@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-12-15virtiofsd: replace _Static_assert with QEMU_BUILD_BUG_ONMarc-André Lureau1-10/+1
This allows to get rid of a check for older GCC version (which was a bit bogus too since it was falling back on c++ version..) Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20201210134752.780923-7-marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-12-10Clean up includesMarkus Armbruster14-67/+0
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes, with the changes to the following files manually reverted: contrib/libvhost-user/libvhost-user-glib.h contrib/libvhost-user/libvhost-user.c contrib/libvhost-user/libvhost-user.h contrib/plugins/hotblocks.c contrib/plugins/hotpages.c contrib/plugins/howvec.c contrib/plugins/lockstep.c linux-user/mips64/cpu_loop.c linux-user/mips64/signal.c linux-user/sparc64/cpu_loop.c linux-user/sparc64/signal.c linux-user/x86_64/cpu_loop.c linux-user/x86_64/signal.c target/s390x/gen-features.c tests/fp/platform.h tests/migration/s390x/a-b-bios.c tests/plugin/bb.c tests/plugin/empty.c tests/plugin/insn.c tests/plugin/mem.c tests/test-rcu-simpleq.c tests/test-rcu-slist.c tests/test-rcu-tailq.c tests/uefi-test-tools/UefiTestToolsPkg/BiosTablesTest/BiosTablesTest.c contrib/plugins/, tests/plugin/, and tests/test-rcu-slist.c appear not to include osdep.h intentionally. The remaining reverts are the same as in commit bbfff19688d. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20201113061216.2483385-1-armbru@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Tested-by: Thomas Huth <thuth@redhat.com> Acked-by: Cornelia Huck <cohuck@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Acked-by: Alexander Bulekov <alxndr@bu.edu>
2020-12-08libvhost-user: make it a meson subprojectMarc-André Lureau2-3/+2
By making libvhost-user a subproject, check it builds standalone (without the global QEMU cflags etc). Note that the library still relies on QEMU include/qemu/atomic.h and linux_headers/. Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com> Message-Id: <20201125100640.366523-6-marcandre.lureau@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2020-11-12virtiofsd: check whether strdup lo.source return NULL in main funcHaotian Li1-0/+4
In main func, strdup lo.source may fail. So check whether strdup lo.source return NULL before using it. Signed-off-by: Haotian Li <lihaotian9@huawei.com> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Message-Id: <f1e48ca8-d6de-d901-63c8-4f4024bda518@huawei.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-11-12virtiofsd: check whether lo_map_reserve returns NULL in, main funcHaotian Li1-1/+11
In main func, func lo_map_reserve is called without NULL check. If reallocing new_elems fails in func lo_map_grow, the func lo_map_reserve may return NULL. We should check whether lo_map_reserve returns NULL before using it. Signed-off-by: Haotian Li <lihaotian9@huawei.com> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Message-Id: <48887813-1c95-048c-6d10-48e3dd2bac71@huawei.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-11-12tools/virtiofsd/buffer.c: check whether buf is NULL in fuse_bufvec_advance funcHaotian Li1-0/+4
In fuse_bufvec_advance func, calling fuse_bufvec_current func may return NULL, so we should check whether buf is NULL before using it. Signed-off-by: Haotian Li <lihaotian9@huawei.com> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Message-Id: <29fc87c2-b87c-4c34-40d4-75381f228849@huawei.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-11-12virtiofsd: Announce submounts even without statx()Max Reitz1-8/+0
Contrary to what the check (and warning) in lo_init() claims, we can announce submounts just fine even without statx() -- the check is based on comparing both the mount ID and st_dev of parent and child. Without statx(), we will not have the mount ID; but we always have st_dev. The only problems we have (without statx() and its mount ID) are: (1) Mounting the same device twice may lead to both trees being treated as exactly the same tree by virtiofsd. But that is a problem that is completely independent of mirroring host submounts in the guest. Both submount roots will still show the FUSE_SUBMOUNT flag, because their st_dev still differs from their respective parent. (2) There is only one exception to (1), and that is if you mount a device inside a mount of itself: Then, its st_dev will be the same as that of its parent, and so without a mount ID, virtiofsd will not be able to recognize the nested mount's root as a submount. However, thanks to virtiofsd then treating both trees as exactly the same tree, it will be caught up in a loop when the guest tries to examine the nested submount, so the guest will always see nothing but an ELOOP there. Therefore, this case is just fully broken without statx(), whether we check for submounts (based on st_dev) or not. All in all, checking for submounts works well even without comparing the mount ID (i.e., without statx()). The only concern is an edge case that, without statx() mount IDs, is utterly broken anyway. Thus, drop said check in lo_init(). Reported-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com> Message-Id: <20201103164135.169325-1-mreitz@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
2020-11-03meson: vhost-user-gpu/virtiofsd: use absolute pathMarc Hartmayer1-1/+1
The option `libexecdir` is relative to `prefix` (see https://mesonbuild.com/Builtin-options.html), so we have to be aware of this when creating 50-qemu-gpu.json and 50-qemu-virtiofsd.json. Otherwise, tools like libvirt will not be able to find the executable. Fixes: 16bf7a3326d8 ("configure: move directory options from config-host.mak to meson") Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com> Message-Id: <20201103112333.24734-1-mhartmay@linux.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2020-11-02virtiofsd: Announce sub-mount pointsMax Reitz2-0/+23
Whenever we encounter a directory with an st_dev or mount ID that differs from that of its parent, we set the FUSE_ATTR_SUBMOUNT flag so the guest can create a submount for it. We only need to do so in lo_do_lookup(). The following functions return a fuse_attr object: - lo_create(), though fuse_reply_create(): Calls lo_do_lookup(). - lo_lookup(), though fuse_reply_entry(): Calls lo_do_lookup(). - lo_mknod_symlink(), through fuse_reply_entry(): Calls lo_do_lookup(). - lo_link(), through fuse_reply_entry(): Creating a link cannot create a submount, so there is no need to check for it. - lo_getattr(), through fuse_reply_attr(): Announcing submounts when the node is first detected (at lookup) is sufficient. We do not need to return the submount attribute later. - lo_do_readdir(), through fuse_add_direntry_plus(): Calls lo_do_lookup(). Make announcing submounts optional, so submounts are only announced to the guest with the announce_submounts option. Some users may prefer the current behavior, so that the guest learns nothing about the host mount structure. (announce_submounts is force-disabled when the guest does not present the FUSE_SUBMOUNTS capability, or when there is no statx().) Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20201102161859.156603-6-mreitz@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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